As far as PTSD is concerned, I remember a commentary / documentation (I suck at keeping my sources, so...) that went a long these lines:
- War was more common, when everybody is kind of traumatized, society copes with it better - soldiers were traumatized, but it seems less so when compared to modern war, which brings me to the last point: - the most horrible war experience back then was battles (sieges, field battles,...), off battle, life for the soldier was as dangerous as a civilian's one. In modern war, the soldiers stress was constant, everywhere and the enemy (artillery, snipers, air craft,...) often invisible, increasing the stress levels a lot
I am no expert in psychology, but it does sound logical.
It doesn't mean they loved their children less. It means they had a different bar before they considered them full-fledged "children." In lots of cultures they don't name kids for a few days or weeks. In pre-modern China, infanticide within the first few days of birth was considered a normal, though regrettable, form of birth control. There's even the story about how Spartans used to leave children who were too sickly to the wolves.
You can see this sliding standard in modern times too with the abortion debate. Some evangelicals get VERY intense about the life of the fetus in utero. For some of the more hardcore ones, even very early stage miscarriages get funerals and the zygote gets regarded with all the honors that a child would have been. In their minds, an abortion is infanticide without a doubt. Meanwhile, other people think of it as a routine medical procedure and think the evangelical position is parodic on the level of "Every Sperm is Sacred."
But overall, the point isn't that they didn't feel the feelings. It's that they had better ways of processing and working through them.